In the deployment of a graft or stent graft into the human or animal body via intraluminal techniques a deployment device is used to introduce the graft into a lumen of the body and, after the graft has been deployed and expanded within the lumen, the introducer needs to be retracted.
One form of introducer uses a proximal nose cone with a distally facing capsule to encompass an exposed stent and barbs on the exposed stent of a stent graft during introduction and, after the stent graft has been released and the capsule has been removed from the exposed stent, the capsule along with the introducer must be withdrawn. The capsule, however, has a distally facing opening with an edge surrounding it and this edge can engage with stents of the just introduced stent graft and cause problems with dislodging the stent graft from its position on the wall of the lumen. Similarly, an introducer often has a sheath which is used to constrain a stent or stent graft during delivery and this sheath is withdrawn from the stent or stent graft to release the stent or stent graft. This sheath has a proximally facing opening and a surrounding edge so if the sheath is advanced to meet the distally facing capsule then that edge may engage with stents of the just introduced stent graft and cause problems with dislodging the stent graft from its position on the wall of the lumen. It is desirable to engage the sheath with the capsule before withdrawal and hence some way of preventing the edges as discussed above from dislodging the stent graft is desirable.
It is the object of this invention to address one or more of the above problems or at least to provide the practitioner in the field with a useful alternative device.
Throughout this specification the term distal with respect to a portion of the aorta, a deployment device or a prosthesis means the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart and the term proximal means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood.